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wmo-im / iwxxm

XML schema and Schematron for aviation weather data exchange
https://old.wmo.int/wiswiki/tiki-index.php%3Fpage=TT-AvXML
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Add explicit TL/AT/FM to METAR/SPECI Trend Forecast #7

Closed marqh closed 6 years ago

marqh commented 7 years ago

Some ambiguity remains regarding how to interpret the trend forecast group portion of METAR/SPECI. Currently the TL, FM, or AT determination is carried only by the phenomenonTime and whether it is before or after other time portions of the trend forecast. In TT-Av-XML-4 it was determined to be less confusing to make an explicit option to indicate TL, AT, and FM for the relevant forecast change groups in addition to the current time indicators.

ref: https://software.ecmwf.int/issues/browse/AVXML-13

Created: 29/Sep/15 8:59 PM

Reporter: Aaron Braeckel

braeckel commented 6 years ago

This is closely related to #13

blchoy commented 6 years ago

Interestingly, the gml:TimePeriod in each trend forecast block should provide adequate information on the valid period of the phenomena involved. The TL/AT/FM included in the IWXXM instance has no specific value except for backward (IWXXM-to-TAC) conversion. As it has been determined that IWXXM-to-TAC shall not be carried out, once the text rendering format has been determined and there is no need to indicate TL/AT/FM, we may want to remove this description then.